On Thu, Jun 2, 2016, at 12:34 AM, Gregg Eshelman wrote: > There's bound to be some roller chain size between that and bicycle chain, > which would be ideal for your application.
Unless this is a mighty slow lathe, I don't think chain is the appropriate drive mechanism. It sounds like part of the problem is a spindle pulley that is too small. That hurts twice. First, it reduces the lever arm and requires more belt pull per ft-lb of torque delivered. Second, it reduces the belt wrap and number of teeth engaged, which increases the load per tooth even more. Bigger pulleys help in other ways too. A big spindle pulley provides some flywheel effect which can reduce chatter and relieves the motor/belt of the worst shock loads. I've never seen this lathe, only tried to parse Gene's written explanations. So I have no idea what the real limitations are as far as pulley size, belt width, etc. A photo or two of the spindle area would help. What are the real constraints on pulley size and drivetrain configuration? Also helpful would be the following: Motor rated power (hp or watts, at a particular speed) Motor rated speed (at which it develops rated HP) Motor speed range when used with the drive in question Desired spindle speed range >From that information, you can use online resources to determine the proper type and size of belt and the proper pulleys to design a reliable drivetrain. Once you know what you need, then you figure out how to make it fit. This chart is a good starting point. http://www.sdp-si.com/D265/HTML/D265T006.html Given the rated HP and the speed of the faster pulley it shows you which belt families can handle the power. Doing it any other way is bass-ackwards IMHO. It sounds like the existing belt is an XL series. According to the chart, the maximum power for an XL belt is about 1/2HP at 3450 RPM, about 1/3HP at 1750 RPM. And that assumes properly chosen belt widths (not 3/8") and pulley sizes. If you've increased the motor beyond those limits (or even close to them), there is simply no way it is going to be reliable. Another option instead of timing belts is multi-groove V-belts (J series). They have the advantage that you can make your own pulleys (if you have a working lathe). A spindle drive shouldn't need positive registration, so you don't really need toothed belts. -- John Kasunich jmkasun...@fastmail.fm ------------------------------------------------------------------------------ What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic patterns at an interface-level. Reveals which users, apps, and protocols are consuming the most bandwidth. Provides multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make informed decisions using capacity planning reports. https://ad.doubleclick.net/ddm/clk/305295220;132659582;e _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
